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Structural basis of ligand recognition by PABC, a highly specific peptide‐binding domain found in poly(A)‐binding protein and a HECT ubiquitin ligase
Author(s) -
Kozlov Guennadi,
De Crescenzo Gregory,
Lim Nadia S,
Siddiqui Nadeem,
Fantus Daniel,
Kahvejian Avak,
Trempe JeanFrançois,
Elias Demetra,
Ekiel Irena,
Sonenberg Nahum,
O'ConnorMcCourt Maureen,
Gehring Kalle
Publication year - 2004
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/sj.emboj.7600048
Subject(s) - biology , ubiquitin ligase , ubiquitin , peptide , plasma protein binding , dna ligase , ubiquitin protein ligases , ligand (biochemistry) , domain (mathematical analysis) , microbiology and biotechnology , binding site , biochemistry , biophysics , computational biology , receptor , enzyme , gene , mathematical analysis , mathematics
The C‐terminal domain of poly(A)‐binding protein (PABC) is a peptide‐binding domain found in poly(A)‐binding proteins (PABPs) and a HECT ( h omologous to E 6‐AP C ‐ t erminus) family E3 ubiquitin ligase. In protein synthesis, the PABC domain of PABP functions to recruit several translation factors possessing the PABP‐interacting motif 2 (PAM2) to the mRNA poly(A) tail. We have determined the solution structure of the human PABC domain in complex with two peptides from PABP‐interacting protein‐1 (Paip1) and Paip2. The structures show a novel mode of peptide recognition, in which the peptide binds as a pair of β‐turns with extensive hydrophobic, electrostatic and aromatic stacking interactions. Mutagenesis of PABC and peptide residues was used to identify key protein–peptide interactions and quantified by isothermal calorimetry, surface plasmon resonance and GST pull‐down assays. The results provide insight into the specificity of PABC in mediating PABP–protein interactions.